Bottom Line:
Although the physiological effects of the plant extract were predicted as a result of the alterations in protein expression, the key protein(s) involved in these alterations are still unclear.We observed that alpha-2-HS glycoprotein (AHS) was significantly decreased in the serum of experimentally treated rats compared to pre-treated animals.Moreover, reduction in AHS was confirmed using competitive enzyme-linked immunosorbent assay.

Affiliation: Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya Kuala Lumpur, Malaysia ; Oral Cancer Research and Coordinating Centre, Faculty of Dentistry, University of Malaya Kuala Lumpur, Malaysia.

ABSTRACTEurycoma longifolia is a Malaysian native herb that has been widely used as an aphrodisiac and a remedy for andropause. Although the physiological effects of the plant extract were predicted as a result of the alterations in protein expression, the key protein(s) involved in these alterations are still unclear. In the present study, we have investigated the effect of standardized E. longifolia extract on serum protein expression up to 28 days following oral administration in rats. Serum protein profiles were analyzed by 2-dimensional electrophoresis, and altered proteins were identified via mass spectrometry. We observed that alpha-2-HS glycoprotein (AHS) was significantly decreased in the serum of experimentally treated rats compared to pre-treated animals. Moreover, reduction in AHS was confirmed using competitive enzyme-linked immunosorbent assay. AHS expression is known to be associated with insulin resistance and diabetes. Our data indicated that serum AHS was reduced in rats treated with standardized E. longifolia extract, and therefore form a prelude for further investigation into the effects of this natural extract in animal models involving infertility and diabetes.

Mentions:
We recently provided evidence that eurycomanone obtained from the standardized extract F2 could improved spermatogenesis and fertility in rats (Low et al., 2013). The validated HPLC method for the phytochemical analysis of the active constituents in the standardized extract F2 was found to contain 34.14% w/w of the major bioactive quassinoids, comprising 13α(21)-epoxyeurycomanone (1) (7.39 ± 0.17%, w/w), eurycomanone (2) (14.49 ± 0.26%, w/w), 13,21-dihydroeurycomanone (3) (0.72 ± 0.06%, w/w) and eurycomanol (4) (9.54 ± 0.22%, w/w) (Figure 1) (Low et al., 2013). In fact, we observed elevation of testosterone, luteinizing hormone, and follicle stimulating hormone in plasma, along with suppression of estrogen, after oral administration of E. longifolia extract, revealing its effect on the hypothalamic-pituitary-gonadal axis (Low et al., 2013). This increase in male fertility and hormones following treatment with the quassinoid-rich E. longifolia extract suggests that it may alter animal physiology. However, no study has identified the protein(s) linking eurycomanone to its in vivo physiological effects. Although it is predicted that these physiological changes result from alterations in protein expression following E. longifolia treatment, it remains unclear which proteins might be affected (Tsai and Wiltbank, 1998). Thus, the aim of this study was to investigate serum proteomic profile changes following administration of standardized bioactive E. longifolia in an animal model. E. longifolia-treated male Sprague-Dawley rats were compared to pre-treated animals over 28 days, and serum proteins were analyzed using two-dimensional gel electrophoresis (2-DE) and subsequently identified via mass spectrometry (MS).

Mentions:
We recently provided evidence that eurycomanone obtained from the standardized extract F2 could improved spermatogenesis and fertility in rats (Low et al., 2013). The validated HPLC method for the phytochemical analysis of the active constituents in the standardized extract F2 was found to contain 34.14% w/w of the major bioactive quassinoids, comprising 13α(21)-epoxyeurycomanone (1) (7.39 ± 0.17%, w/w), eurycomanone (2) (14.49 ± 0.26%, w/w), 13,21-dihydroeurycomanone (3) (0.72 ± 0.06%, w/w) and eurycomanol (4) (9.54 ± 0.22%, w/w) (Figure 1) (Low et al., 2013). In fact, we observed elevation of testosterone, luteinizing hormone, and follicle stimulating hormone in plasma, along with suppression of estrogen, after oral administration of E. longifolia extract, revealing its effect on the hypothalamic-pituitary-gonadal axis (Low et al., 2013). This increase in male fertility and hormones following treatment with the quassinoid-rich E. longifolia extract suggests that it may alter animal physiology. However, no study has identified the protein(s) linking eurycomanone to its in vivo physiological effects. Although it is predicted that these physiological changes result from alterations in protein expression following E. longifolia treatment, it remains unclear which proteins might be affected (Tsai and Wiltbank, 1998). Thus, the aim of this study was to investigate serum proteomic profile changes following administration of standardized bioactive E. longifolia in an animal model. E. longifolia-treated male Sprague-Dawley rats were compared to pre-treated animals over 28 days, and serum proteins were analyzed using two-dimensional gel electrophoresis (2-DE) and subsequently identified via mass spectrometry (MS).

Bottom Line:
Although the physiological effects of the plant extract were predicted as a result of the alterations in protein expression, the key protein(s) involved in these alterations are still unclear.We observed that alpha-2-HS glycoprotein (AHS) was significantly decreased in the serum of experimentally treated rats compared to pre-treated animals.Moreover, reduction in AHS was confirmed using competitive enzyme-linked immunosorbent assay.

Affiliation:
Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya Kuala Lumpur, Malaysia ; Oral Cancer Research and Coordinating Centre, Faculty of Dentistry, University of Malaya Kuala Lumpur, Malaysia.

ABSTRACTEurycoma longifolia is a Malaysian native herb that has been widely used as an aphrodisiac and a remedy for andropause. Although the physiological effects of the plant extract were predicted as a result of the alterations in protein expression, the key protein(s) involved in these alterations are still unclear. In the present study, we have investigated the effect of standardized E. longifolia extract on serum protein expression up to 28 days following oral administration in rats. Serum protein profiles were analyzed by 2-dimensional electrophoresis, and altered proteins were identified via mass spectrometry. We observed that alpha-2-HS glycoprotein (AHS) was significantly decreased in the serum of experimentally treated rats compared to pre-treated animals. Moreover, reduction in AHS was confirmed using competitive enzyme-linked immunosorbent assay. AHS expression is known to be associated with insulin resistance and diabetes. Our data indicated that serum AHS was reduced in rats treated with standardized E. longifolia extract, and therefore form a prelude for further investigation into the effects of this natural extract in animal models involving infertility and diabetes.